Emerging infectious diseases, vaccines and Guillain-Barré syndrome.

The recent outbreak of Zika virus infection increased the incidence of Guillain-Barré syndrome (GBS). Following the first reported case of GBS after Zika virus infection in 2013, there has been a considerable increase in the incidence of GBS in endemic countries, such as French Polynesia and Latin American countries. The association between coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and GBS is another emerging research hotspot. Electrophysiological studies have suggested that GBS patients associated with Zika virus infection or COVID-19 tend to manifest acute inflammatory demyelinating polyneuropathy, rather than acute motor axonal neuropathy (AMAN). Causative autoantibodies, such as anti-ganglioside antibodies in AMAN associated with infection, have not been identified in GBS associated with these emerging infectious diseases. Nevertheless, recent studies suggested molecular mimicry between these viruses and human proteins related to GBS. Recent studies have shown the efficacy of new vaccines, containing artificial messenger RNA encoding the spike protein of SARS-CoV-2, against COVID-19. These vaccines are now available in many countries and massive vaccination campaigns are currently ongoing. Although there are long-standing concerns about the increased risk of GBS after inoculation of conventional vaccines, the risk of GBS is not considered a legitimate reason to limit administration of currently available vaccines, because the benefits outweigh the risks.